Process for producing hydrocarbons



Aug. 24, 1943. F. E. FREY EI'AL- I ,3

PROQE SS.FOR PRODUCING HYDROCARBONS Original Filed Oct 19, 1936 INVENTORFREDERICK E. FREY Hallow a. M

ATTORNEYS Patented Au 24, 1943.

UNITED" STATE PRDCES$ F013 FredericEE. Frey and Harold J. Hepp,

PRODUCING unmo- ARBO Bar-ties? ville, .0kla., assignors to PhillipsPetroleum Company, a corporation of Delaware Original applicationOctober 19, 1936, Serial No. 106,482. Divided and this application April27, 1940, Serial No. 332,090

2 Claims.

This invention relates to the production of paraffin hydrocarbons andparaffinic motor fuels of normal gasoline boiling range from hydrocarbonmaterial of lower boiling temperatures, and

more specifically to-the reaction of simple olefin I and paraffinhydrocarbons to produce especially valuable motor fuels and paraffinhydrocarbonsof branched structure.

This application is a division of our copending application, Serial No.106,482, filed October 19, l

1936, entitled, "Process for producing hyd ocarlions, now U. S. Patent2,209,450, granted July 30, 1940.

An object of this invention is to produce a liquid motor fuelessentiallyparaifinic in nature, without resorting to olefinic polymerformation and the subsequent hydrogenation of the olefin hydrocarbons.

Another object of this invention is the use of a synthetic conversionstock composed of hydrocarbons of simple and controlled composition toproduce a liquid motor fuel having especially desirable characteristicsand controlled properties, reflecting the identity of the reactanthydrocar bons selected.

A further object is the production of individual paraffin hydrocarbonsof purity and identity not attainable from natural products nor as theresultof usual operations for hydrocarbon manufacture.

Another object is the production of various branched parafiins of asingle species or a mixture of simple composition within a wide range ofboiling points or volatilities.

Still another object is the production of valuable parafiinic chemicalraw materials, such as ne'opentane (2,2-dimethylpropane) and neohax-.ane (2,2-dimethylbutane) which may be chlorinated to yieldpredominantly the relatively non-corrosive primary chlorides. vI

Further objects of our invention will become apparent as the followingdiscussion proceeds.

A number of methods have been proposed for the production of highermolecular weight hydrocarbons from normally gaseous hydrocarbons such asare found in the residue gases from natural gasoline plants or thedistillation and cracking of petroleum.

It has been proposed to convert hydrocarbon gases,-consistingessentially of parafiins higher than methane, or consisting of olefinsor their mixtures such as are produced by the foregoing methods, by heatand pressure into hydrocarbons of higher molecular weight. By such meansnormally liquid hydrocarbons suitable for motorfuel are produced.Polymerization of olefins directly into'larger molecules is thuseffected, while paraffins so treated are thermally split into smallermolecules, part of which are olefins, which concurrently polymerize. Ithas also been pro-' posed to decompose paraflins thermallyinto olefinsat a low reaction pressure, thereby favoring the eflicient production ofsimple olefins, which may subsequently be polymerized by a heat andpressure conversion step. Under particularly drastic temperatureconditions, the olefinic, paraflinic and heterocyclic polymers aredecomposed and normally liquid hydrocarbons of simple composition, butof aromatic structure, survive-by reason of the heat stable character ofaromatic hydrocarbons. The milder conversion'temperatures which lead-toaliphatic liquid hydrocarbons yield products rich in olefins, andsometimes paraiiins, but of exceedingly complex composition, this partlyby reason of the high velocity of concomitant secondary reactions,

Such normally liquid hydrocarbon fuels are ordinarily suitable for useas motor fuel in internal combustion engines but difficulties arise fromtheir use under the exacting conditions encountered in certain types ofengines such as the high compression type used in aircraft. Thusolefinic and aromatic fuels often lead to excessive heating and variableperformance with modification in engine design. Moreover, use ofunsaturated hydrocarbons in motor fuels may lead to deterioration ofantidetonation qualities during storage as well as formation-of gum,which causes deposits in fuel systems and on valves. Fuels composed ofparafiinic hydrocarbons possess characteristics such that thesedifficulties do not arise. It is well known that paraffins of branchedstructures possess excellent antidetonating character-v istics andcomparative freedom from heating tendencies in high compression engines.Paraffin" of normal structure, on the other hand,

have strong detonating characteristics and are to considerable expensein producing in this way branched paraflins meeting both antidetonatingferred to there have been described methods for producing motor fuelhydrocarbons predominating in branched paraffins by reacting togetheroleflns and parafflns under heat and pressure With suitable control ofolefin concentration during reaction.

Thus in U. S. Patent 2,002,394 issued to Frederick E. Frey on May 21,1935, covering a Process for converting hydrocarbons it was proposed toadd at a plurality of points olefins to a parafiinic hydrocarbon streamunder the influence of ele vated temperature and pressure to produce amotor fuel predominating in branched parafiins. In the copendingapplication, Serial Number 12,981, filed March 25, 1936, by Frederick E;Frey relating to a Process for converting hydrocarbons, now U. S. Patent2,104,296, granted January 4, 1938, there is proposed a process whereinthe exothermic heat of reaction between olefins. and parafilnic materialassists in controlling the reaction temperature level. Also in thecopending application Serial Number 82,954 filed June 1. 1936, byFrederick E. Frey relating to a Process for converting hydrocarbons, nowPatent 2,270,-

700, granted January 20, 1942, there is described a process formanufacturing motor fuel from raw hydrocarbons deficient in olefincontent.

We have discovered that under suitable conditions of conducting theconversion operation the simple juncture of parafiins with olefins canbe effected, with limited extent of secondar and concomitant reactions,to yield a product of sim-.

ple molecular composition consisting essentially of such resultingjuncture compounds of paraffinic type, and this is apart of ourinvention. We have discovered that under such conditions the identity ofthe paraflins produced refiects'the identity of the reactant parafilnsand olefins, the thermal conversion being of the nature of a con trolledchemical synthesis. It is a part of our invention to react togetherselected single species of parafllns and olefins, or simple mixtures toproduce at will individual paraflins and simple mixtures of variousdesired structures and varying boiling points and molecular weights. Itis possible to apply fractional distillation economically to suchproducts to procure desired paraiiins in a pure or concentrated state.

According to the present invention a paraflin hydrocarbon in it purestate is maintained at a pressure of 1,000 to 10,000 pounds or more persquare inch and is at the sametime maintained at a reaction temperaturesuch that decomposition reactions are slight and less than 10 per centand preferably less than 5 per cent of the paraflln undergoes fracturereactions. Suitable temperatures are found to lie between 750 and 1100F., and while thus heating under prefisure in the range described, theolefin is maintained dispersed in the paraflin in a low concentration,less than weight per cent. The juncture of paramn with olefin takesplace essentially according to the equation iii) unaccompanied byextensive juncture of olefin with olefin by reason of the, lowconcentration of olefin present. The reaction is then interrupted andthe parafilns thus formed are separated from the products. An olefin inconcentration of less than 10 per cent may be initially introduced intothe parafiin and the heating conducted in any conventional manner, suchas by passage through a heated tube coil to produce a limited yield ofsynthetic paraflins. If it is desired to react over v10 per cent oftotal olefin, introduction of olefin is made to thereacting mixtureduring the course of the reaction as olefin is consumed, the additionbeing made in such a manner that the concentration of unreacted olefinin the reacting mixture is maintained at a desired low level. This may'be accomplished by introducing olefin at a plurality of pointsdistributed along a tube coil through which the reacting mixture flows,or an olefin'rich paraiiin-olefin mixture may be injected into areaction chamber in which an essentially parafiinic mixture is dispersedand mixed with the reacting mixture while the latter is circulated inthe reaction chamber so as to flow the partially reacted mixturerepeatedly past the point of dispersal. A simple apparatus for thismanner of conversion may include an enlarged reaction chamber into whichthe paraffimolefir. mixture is injected at a velocity sufficient to shea dispersal in the reacting mixture and main 2 turbulence and an activecirculation of the iota; mixture through a heating zone and past thepoint of injection; Such means are described in the applications heretoreferred to and identified, and other equivalent means will be apparent.

The formation of the desired paraffins in a state of relative purity isfavored by particularly high pressures while a low concentration ofolefin is maintained, ranging from 1 to 5 per cent, for example, at4,000 pounds pressure per square inch. Pressures of 2,000 to 3,000pounds per square inch and more are preferable. At a pressure as low as1,000 pounds paraflins are synthesized in somewhat less purity but theproducts are predominantly the juncture compounds oi, the olefin andparaffin reacted if their production is limited to less than 10 per centof the total reactants per thermal treatment with correspondingly lowolefin content, which in such a case may b below 10 per cent, and betterif below 5 per cent, Ethylene undergoes somewhat more efficient juncturewith paraflins than do the higher olefins under such low pressureconditions. As higher concentrations of paraflins are built up thethermodynamic limit for the reaction is approached and the syntheticparafilns undergo decomposition, yielding a product which while rich inisoparamns, acquires a very complex composition. High conversionpressures permit in creased formation of desirable products, which mayamount to 30 per cent of the reaction mixture at 5,000 to 10,000 poundsper square inch.

fractional distillation is dependent on the materials involved and canbe readily determined by trial. .By the partial conversion of thereactant paramns will be understood the limitation of'ex-.

tent of conversion in accordance with the fcregoing description.

The temperature and reaction time should be such as will eflect theconversion with only a small extent of splitting reactions. Theconditions are readily determined by trial and typical conditions areset. forth in the examples to be presented.

All paraflin hydrocarbons undergo reaction with olefins, for example thejuncture. of ethylene taking place most readily with the replacement oftertiary hydrogen by ethyl,- less readily in replacing secondaryhydrogen, and least readily in replacing primary hydrogen. Methane andethane'react at a somewhat slower rate than the higher paraflins underequivalent conditions;

Olefins of varying structure and molecular weight a reaction zone may beaccomplished in a number undergo reaction with parafiins, the higherreaction pressures, or low extent of conversion per thermal treatmentbeing usually'required with increasing number of alkyl substituentsattached to the ethylene molecule, if a product rich in primaryolefin-'parafiin juncture products is desired.

While reactant parafiins and olefins consisting each of a singlemolecular species are particularly desirable to yield paraffln productsof s mple composition, it is sometimes desirable to use simple mixturesto obtain a desired result. Thus, ethylene and isobutane react toproduce hexanes, but a required or specified motor fuel of somewhatlower volatility and gradually rising distillation curve may be producedby reacting both et ylene and propylene with the isobutane wherebyheptanes together with hexanes, both of highly branched structure, maybe produced to meet a distillation curve specification of this kind. Theolefins may be introduced at separate points or may be mixed prior tothe introduction. For economic reasons it is sometimes preferable to usesimple mixtures, thus ethylene produced by pyrolysis toserve as areactant may be associated with more or less of difilculty reactingethane when absorption or distillation are used to separate the ethylenefrom other pyrolysis products. Similarly 2-2-dimeth'ylbutane and2-methylpentane, both hexanes, may be reacted together with ethylene toproduce a mixture of octanes, which are complex and highly branched, butmeeting for motor fuel blending purposes specific volatility andanti-detonating requirements.

The drawing diagrammatically shows one type of apparatus for realizingand eflecting the teachings of this invention.

The process of our invention may be conducted in an apparatus such as isshown in the drawing,

which is a diagrammatic side elevation of ele-- ments, not drawn toscale, and illustrates one means by which the process may be practiced.Referring now to the .drawing, an essentially pure paraflinichydrocarbon is introduced through pipe I and compressed to a suitableworking or reaction pressure by pump II. This pressure will be between1,000 and 10,000 or more pounds per square inch. Having been brought tothis pressure the parafiinic material passesthrough conduit l2 and issubjected to a reaction temperature in 0011 I3, suitably housed in afurnace or heating means I 4. -Such a reaction temperature will bebetween 750 and 1100 F., and willbe such that the total thermaldecomposition of. the paraflin hydrocarbon treated, due to its exposureto said temperature, will be less than 5 per cent by weight for reactionperiods which may range from about 1 toabout 30 minutes, the mostsuitable exact conditions being determined by trial. While under theseconditions there is admixed with the paraflin hydrocarbon, in a mannerto be hereinof diii'erent ways. An olefin hydrocarbon, either in a purestate or somewhat diluted by the material introduced through pipe I0, isintroduced through pipe I! and is compressed by pump It to a suitablepressure and carried by'conduit H to the conduits designated by thereference numer- 'als It to inclusive, in which the fiow is controlledby valves designated 'by the reference numerals 21 to inclusive,respectively. Another olefin hydrocarbon, also either in a pure state orsomewhat-diluted by the material introduced through pipe I, may beintroduced. as will e discussed later, through pipe 36 and compressed bypump 31 to a suitable pressure and carried by conduit 38 to the conduitsdesignated by the reference numerals 39 to 43 inclusive. in which theflow is controlled by the valves designated by the reference numerals 44to 48 inclusive, respectively, and which conduits lead to the conduitsl8, l 9, 20, 2| and 22 respectively. Hydrogen may be introduced as willbe discussed, through pipe 49, and compressed by pump 50 to a suitablepressure, and passed through the conduit ii to conduits 52, 53, and 54.The hydrogen is passed through these conduits and is controlled'byvalves 55, 58 and 51 respectively, and passed to conduits 39, 40 and llrespectively and thence on through conduits l8, I9 and 20 respectivelyand thence into the reaction coil l3.

In one mode of operation the valves 44 to 4B inelusive, and the valves55, 56 and 51 are closed, and valves 21 to 35 inclusive are socontrolled that a limited quantity of the olefin, introduced throughpipe l5, passes to the reaction through each of them, the total amountof unreacted ole-- fin at any one point not exceeding 10 per cent byweight of the hydrocarbons present at that point. With such a procedureeilluents from the reaction coil l3 will paw through conduit 58 andvalves 59 and 60 to the separating means 6! with valve 62 in conduit 63and the valve 64 in conduit 65, which conduits make connection with theinsu-. lated reaction chamber 66, being closed as will be the valve 01in conduit 68. The pressure in separating means 6|, which will besomewhat lower than the reaction pressure, is controlled by the valveill.

Another mode of operation, involving the addia of paraflinhydrocarbons.being introduced through conduits 22, 24, 2! and 26, valves 21 to 3iinclusively being closed. The flow of this olefin into the mixturethrough pipes 23, 24-, 25 and 26 is controlled by valves 32, 33, 34 and35 respectively. Another olefin, either in a pure state or somewhatdiluted by the material introduced through pipe III, is introducedthrough pipe 36, compressed to a suitable pressure by pump 31 and passedthrough conduit 38 and into the reacting mixture through conduits 39 to43 inclusive and conduits [8 to 22 inclusive, valves 21 to 3| inclusivebeing closed as mentioned, and valves 55, 58 and 51 also being closed.The flow of this second olefin stream is controlled by valves to 43inclusive respectively. In such a mode of op eration the parafllnhydrocarbon introduced through pipe I is reacted first with one olefinto form a higher molecular weight paramn hydrocarbon as a product andthen with another olefin to form a similar higher molecular weightparaflln hydrocarbon as a product which, however, contains a differentnumber of carbon atoms per molecule than does the first mentionedproduct. Eiiiuents of the reaction coil I3 pass directly to theseparator 6| as heretofore described.

Higher molecular weight hydrocarbon material produced'in this manner ispredominantly composed of relatively few species of paraflinichydrocarbon molecules, most of which have a more or less highly branchedstructure. A certain limited amount of oleflnic material usuallypolymerized with itself, forming a limited amount of higher molecularweight olefins. Although heavier hydrocarbon material recovered as afinal product is essentially paramnic in nature, it may be desirablefurther to decrease any olefinic molecular species. We have found thathydrogen introduced into the last part of the reaction coil, afterparaffin-olefin polymerization reactions have been essentiallycompleted, will react with olefin present, to form the correspondingparaflln hydrocarbons.

This addition to our process may be included in either of the above twomodes of operation. In either case, when the olefin content is low,hydrogenation maybe practiced as follows. Valve 21, in conduit i8, isclosed, as is valve 44, in conduit 33. Hydrogen is introduced throughpipe 43, compressed by pump to a suitabie'pressure, and passed byconduit 5| to conduit I52, valves 56 and 51 in conduits 53 and 54 beingclosed. The flow of hydrogen through the conduit 52 is controlled byvalve 55, and continues through conduit 38 into conduit l8 and into'vthe mixture, reacting with the olefins present in the mixture in thevery last part of the coil l3. The total efliuents of the coil [3 arepassed to separator 8| as has been described.

In another mode of operation the olefin may rating means 8| throughvalve 80, the remaining eiiluents passing through valve 61 and conduit68 to the hot oil pump 69 which forces the stream through conduit I0 andvalve H and into the conduit l2.

The introduction of small amounts of pure fin with itself at the pointof introduction whensuch olefins are introduced into the reaction zone.Thus conduit I! may introduce into the process a mixtureconsistingv ofthe pure paraffin hydro.- carbon introduced through conduit l0, and thepure olefin to be reacted therewith. Also conduit 36 may introduce intothe process a mixture consisting of the pure paraffin hydrocarbons andthe pure olefin to be reacted. In such a case the olefin concentrationpassing through pipes l5 and 36 will be appreciably greater than itsrespective concentration in the reaction mixture as discussedpreviously, and the amount of parafiin hydrocarbon thus introduced withthe olefin is-to be considered when considering the composition of themixture at any point,

The olefin concentration i purposely kept low, so as to favor reactionsinvolving paraflin-olefin juncture and to inhibit polymerization of oneolefin species with itself or with another species.

Because of the high concentration of parafilnic material throughout thereaction coil, more than one olefin species may be introduced forreaction, such introduction being made separately, without going outsidethe scope of this invention. The composition of the higher boilingmaterial thus synthesized will still be simple, and will be introducedonly through conduit II to conduit 1 l3 and through valve 21, while theremaining valves 28 to 35 inclusive, 44 to 48 inclusive and 55, 56 and51 are closed. In such a case, the eifluents may be introducedturbulently into insulated reaction chamber 86, which is eflected byvalve 59 being closed and valve 62 in conduit 83 and valve 64 in conduit6! being open. Coil I3 serves in this one to impart heat suilicient tosustain reaction in chamber 86 but not prematurely to react theolefin-rich mixture in coil l3 when olefin concentration employedtherein exceeds the desired low reaction concentration. All theefliuents from the reaction may pass directly into separating means Si,or valve 6'! in conduit 83 may be partially opened. and only a certainportion of the diluent; allowed to pass into sepaconsist predominantlyof only a few molecular species. Some higher molecular weight olefinichydrocarbons may be formed as a side reaction from polymerization of theolefins introduced. When such olefins are present, hydrogen may be addedas has been discussed, to produce a more completely parafllnic product.'If such olefins are present in a very low concentration, such' as 2 percent by weight or less, hydrogen in not too great an excess may be addedat only one point as shown above. With somewhat larger amounts ofolefins present, two or more points 01' hydrogen addition may bedesirable as provided for in the operation. In such a case, hydrogenadded at any but the last point should be in such a quantity as to beinsumcient for reaction with all the olefin at the point ofintroduction. In this manner excessive development of heat and reactionsinvolving splitting of parafllnic molecules will be inhibited. Whenreaction chamber 88 is used, addition 01' hydrogen will not bedesirable.

In separating means 6| hydrocarbons of high molecular weight will beremoved and discharged through conduit 12 to the separating means 13,wherein any heavier products are separated and discharged throughconduit 14 and valve I5. Hyrocarbon materials of motor fuel boilingrange, consisting predominantly of a limited number of molecularspecies, and essentially paraiiinic in-nature, will pass from separator13 through conduit 16 to i'ractionating means 11, wherein isoparaiiinfractions concenof gasoline hydrccarbo trated as to desired componentsare separated and discharged through conduits l8, 19, 80 and 8| whichare controlled by th valves 82', 93, 84 and 85 respectively. Theproducts maythen receive any further desired purification treatment. 5

The efliuents of the reaction passing into separator 6| and not beingdischarged therefrom by conduit 12 will mainly consist of unreactedreactants, together with any lighter material which may be present orformed from the slight decomposition which usually takes place. Thiscomposite will pass through conduit 95 to other separating means 81,wherein desired separation may be made and unreacted parafiin dischargedthrou h pipe 88 and valve 89, part of which, if desired, may be returnedthrough conduit 90 and valve 9| to conduit III to be subjected again tothe conversion, while lighter material may be discharged through conduit92 and valve 93.

The following examples will further illustrate the novelty andadvantagesof this invention:

' Example I Referring to an apparatus whose essential characteristiosmay be illustrated by reference to the drawing, propane of better than99 per centpurity was introduced through conduit l0 and increased to'4,500 pounds per square inch pressure by pump ll and-led through conduitI! to 'a reaction coil l3 where it was subjected to a reactiontemperature of 950 F. A seven to one recycle ratio was used by propermanipulation.

of valves and 51, the recycle going through conduit 68 to pump 69 andconduit 10 to conduit 12. A small amount of ethylene of greater 3 than99 per cent purity was added through conduit l5, pump l6, conduits l1and 26 and valve 35, no other points of addition being used. The lengthof the reaction coil 13 and the rate of flow through it was such thatthe average exposure of the propane to the reaction tempera- -ture wasabout 4.1 minutes, while maintaining a steady concentration of reactingethylene of 2 per cent. The eflluents of the process passing to theseparator 6| contained 11.2 per cent by weight with unreacted ma terialin such proportion that by appropriate recycling of this unreactedmaterial an ultimate 'yield of per cent by weight of gasoline waspossible. In 100 parts by weight of hydrocarbons charged there were 8.9parts of ethylene and 91.1 parts of propane. The gasoline boilingfraction had the following composition by weight:

IsO-pentane, which has high antidetonatln qualities and whichconstitutes a valuable ingredient of-a' tion fuels, was present in thepentane fraction to the extent or '17 per cent by weight, or 55.5 percent of the total gasoline produced, and was isolated in a pur state byfractional distillation.

I I Example II A procedure essentially identical to that given 7 pureisobutane as the para-fin and pure ethylene as the olefin. In 100 partsby weight of the hydrocarbons charged there were 12.1 parts of ethyleneand 87.9 parts of isobutane. A pressure of 4,500 pounds per square inchwas used and a reaction temperature of 940 F. with a totalexposure timeof about 4 minutes. The products contained 16.1 percent by weight ofgasoline boiling hydrocarbons, with a possible ultimate yield by properrecycling of 89 per cent. The gasoline boiling fraction had thefollowing composition by weight:

- Per cent Pentenes 5.0 Isopentane 3.3 n-Penta 4.9 Hexenes 3.02,2-dimethyl butane.- 44.3 2-methyl pentane 11.5- n-hesmnp 1.1 Heptenes'2.4

, Heptanes 7 4.5 'Octenes 3.9 Octanes 9.6 Residue 6.5

' The fraction consisting of six carbon atoms was 59.9 per cent of thetotalheavier material formed. This fraction consisted oi per cent ofsaturated hydrocarbons, of which 78 per cent was I 2,2-dimethy1 butane,a highly branched paraflin hydrocarbon with very good antidetonatingqualities and a good component for aviation fuels. A 2,2-dimethylbutanefraction was isolated readily in a pure state by fractional distillationand had the following properties: Boiling point degrees Fahrenheit-..121 Reid vapor pressure pounds per square inch 9.5

Density at 27 c 0.642 Gravity at 60 F ..degrees A. P. I 85.2 Unsaturates-per cent.. 0.9

Blended with aviation gasoline blending stock of lower volatility, highanti-knock value and high lead responses were observed. In the purestate, the 2,2-dimethylbutane had an anti-knock value of 95 by the A. S.T. M. method D 357-34T.

This hydrocarbon is particularly suitable as an ingredient of aviationfuel and maybe admixed with appropriate gasoline blending stocks,suitably in a proportion exceeding 5 per cent to impart volatilitywithout excessive vapor pressure as well as improved anti-knock rating.

Example III Following a procedure similar to that given in Example 1,pure isobutane was used as they paraffin and pure isobutylene as theolefin component of the charge stock. In parts by weight of thehydrocarbons charged there were 10.3 parts of isobutylene and 89.! partsof iso-' -reaction temperature of 890? F. was used, with an averagereaction time of about 14.2 minutes.

The products of the reaction contained 10.9 per cent by weight ofhydrocarbons in the gasoline boiling range, with a possible ultimateyield based in Example I was followed, using as reactants 75 on thereacted material by proper recycling, of

' value.

about 92 per cent. The gasoline had the follow- Per cent ing compositionby weight: CsHm 7.7 Per cent CsHn 9.2 C 8.7 CsHiz 3.6 Ce 3.0 5 CsHu 65.0C7 9.8 C'1Hz4 2.2 Ca B. P. 203-223 F 35.5 C'lHlB 6.0 Ca B. P. 223-230 F26.9 Ca+ 6.3 7 Ca B. P. 230 257 F 4.5 Above Ca 11.6 10 100.

The fraction containing eight carbon atoms was 66.9 per cent of thetotal gasoline fraction and was 88 per cent branched octanes, chiefly2,2,4-trimethylpentane and 2,5-dimethylhexane, both of high anti-knockvalue and lower volatility than the hexanes of Example II.

' Example IV Following the procedure as given in Example I a mixturecontaining in 100 parts by weight 95.2 parts of isobutane and 4.8 partsof propylene, was compressed to 4,500 pounds per square inch A fractionconsisting of hexanes, mostly branched, and constituting 65 per cent ofthe gasoline was isolated by fractional distillation containing 95.5 percent hexanes associated with 4.5 per cent of hexenes, the hexanes beingpredominantly 3-methypentane.

Example VIII Following the procedure of Example I, isobutane and2-butene react to form a gasoline with a high content of branchedparafiln hydrocarand treated in the reaction zone at 940 F. for a periodof 7.3 minutes, the fresh charge being introduced to a stream ofcirculating hydrocarbon; the reaction products contained 5.2 per cent ofgasoline boiling range hydrocarbons by weight,

whicnhad the following analysis in parts by The fraction containingseven carbon atoms contained 90 per cent saturated hydrocarbons fromwhich a fraction of highly branched heptanes, with excellentantidetonating characteristics, distilling at 175 to 190 F. wasseparated.

. Example V Following the procedure of Example I, isobutylene andmethane react to yield isopentane and 2,2-dimethylpropane.

Example VI Following the procedure of Example I, isopentane and ethylenewere reacted together to yield branched heptanes of high anti-knockExample VII tion of additional olefin to the reacting mixture notpracticed, contrary to the preceding examples. The products contained8.7 per cent by weight of gasoline hydrocarbons and 30 per cent of theethylene was unreacted. The composition of the gasoline hydrocarbon inper cent by weight was:

bone, and possessing very good antidetonating characteristics. Thegasoline contains over 60 per cent highly branched octanes, of which2,2,3-trimethylpentane and 2,4-dimethyhexane g are predominant members.These octanes are readily separated in high concentrations by fractionaldistillation, the fractions having a low zlolatility and highantidetonating characteris- Although the above detailed descriptionshows some preferred embodiments of this invention. the invention is notto be construed as being limited by such embodiments, and. to theindividual reactants described. What is claimed and desired for LettersPatent is as follows.

we claim:

1. The process of producing normally liquid synthetic predominantlybranched parafllns lying within the motor fuel boiling range by theJuncture of lower boiling parafilns and normally gaseous olefins whichcomprises maintaining a stream of said parafilns in an extended reactionzone at a pressure between 1000 and 10,000

pounds per square inch and at a reaction temperature between 750 and1100 F. for a period of time such that not more than 10 weight per centof the paramns undergo decomposition, in-

troducing said normally gaseous olefins into said parafiins during saidperiod of time in such manher that the concentration of unreactedolefins at no point exceeds 10 weight per cent 01' the total mixtura andin a final portion of said stream after said olefin introduction andafter reaction between said lower boiling parafilns and -said olefins issubstantially complete introducing at a .plurality of sepaarte pointsfree hydrogen in an amount at each point before the last such thatinsufilcient free hydrogen is present to react with a all of theolefinic material present and inan amount at the last point notsubstantially in excess of that required to react with remainingolefinic material but'sufilcient to substantially reduce the amount ofsuch olefinic material. said reaction conditions of temperature andpressure being maintained after the introduction of said hydrogen tocause said hydrogen to react with said olefinic material, the entireprocess being conducted in the absence of a catalyst.

2. The process of producing normally liquid synthetic predominantlybranched parafiins lying within the motor fuel boiling range by theJuneture of lower boiling parafiins with normally gaseous olefins whichcomprises maintaining a stresmoflowerboilingparafilnsinasingleccntinuousextended reaction-zone at apressure of at least 2000 pounds per squareinch-and at a reaction temperature between 750 and 1100 F.

for a period of time not exceeding about 30 minutes and such that thedecomposition of.

paraflins is less than 5 weight per cent. dispersing normally gaseousolefins at a plurality of separate points in said stream duringsaid'period.

of time in such manner that the concentration of unreacted olefin at nopoint in saidstream exceeds 5 weight per cent of the total mixture. andin a final portion of said zone after said points of olefin introductionand after reaction between said lower boiling paraflins and said oleflnsis essentially complete introducing free hydrogen 15 .7

at a plurality' of separate points in an amount at each point beforethe. last such that insufflcient free hydrogen is present to react withall of the .oleflnic material present and in 'an'amount at the lastpoint not substantially in excess 01. that required to react with anyoleflnic material but sufilcient to substantially reduce the amount ofsuch olefinic material, said reaction conditions 01 temperature andpressure being maintained after 10 the introduction oi said hydrogen tocause said hydrogen to react with said oleflnic material the entireprocess being conducted in the absence of catalyst. r

HAROLD J. HEPP.

ZEREDERTCK E. FREY.

